Insulator



July 7 1931- H. M. KRANER 1,813,172

INSULATOR Filed Aug. 29, 1927 A INVENTOR TTORNEY Patented July 7, 1931 UNITED STATES PATENT OFFICE HOBART M. KRANER, OF WILKINSBURG, PENNSYLVANIA, ASSIGNOR T WESTING- HOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYL- VANIA INSULATOR Application led August 29, 1927. Serial No. 216,137.

My invention relates to insulators and particularly to high-voltage insulators for operation under mechanical tension loads.

One object of my invention is to provide 5 an insulator, of the above indicated character, that shall so employ a plurality of inorganic dielectric tension elements as to provide greater tensile strength than would be provided by a single element of the same total cross-sectional area and material.

Another object of my invention is to provide an insulator that shall embody a refractory, vitreous, ceramic or similar dielectric U structure of ready manufacture and improved qualities.

Another object of my invention is to provide a tension insulator of inorganic, refractory or ceramic material that shall avoid the use of relatively great masses of the material and that shall be free of the uneven loading character of thick bodies of this character.

Another object of my invention is to provide a high-voltage tension insulator that shall embody a plurality of exposed insulating rods or elements of permanent moisture-proof character arranged to be free of lateral component forces tending to fracture the same.

Another object of my invention is to pro- -vide a tension insulator that shall subdivide the tension load and that shall also balance the load divisions relative to each other.

Another object of my invention is to provide an insulator thatshall be simple and du- Vrable in construction, economical to manufacture and effective in its operation.

lVith such objects in view, as well as other advantages which may be incident to the utilization of the improvement, the invention `consists in the parts and combinations thereof hereinafter set forth and claimed, with the understanding that the several necessary elements constituting the same may be varied in proportion, arrangement and texture without departing from the nature and scope of the invention.

In high-voltage insulator practice, and especially in outdoor transmission-line service, where the electrical and mechanical loads are comparatively heavy, the weather conditions,

and certain other materials that are coated or covered with one of the inorganic substances above mentioned.

Thile in certain relatively-high-voltage service, the dielectric material is used vunder compression, there are applications where its use under tension is desired.

kBy reason of the relatively hard or unyielding character of the inorganic materials above mentioned, certain of them are not ordinarily so well adapted for use under mechanical tension but, by reason of their high dielectric property and weather resisting character, they are very much to be preferred for insulating high-voltage structures.

It is known that, in certain materials, the

tensile strengthfin pounds per square inch of cross-sectional area increases with decreases of such area, this property being particularly pronounced in hard or brittle materials,

such as porcelain or glass, while not so apparent in fibrous or softer materials. For instance, a quartz rod of one-quarter of an inch diameter has a tensile strength of more an inch in diameter.

It 1s one of my aims to provide amore effective use of the refractory, ceramic or vitrekthan twice that of a similar rod of one third of ous materials in tension wherebystronger and more generally effective insulators are obtained.

Accordingly, in practicing my invention, I provide oppositely spaced terminal structures and a plurality of refractory or similar dielectric elements connected therebetween to so subdivide the tension load as to effect greater total tensile strength than may be obtained by the use of a single element or anyr gli;

col drawings/lier carrying"-v 'the same intbptialeii'ect Without limitingthe improvements in their useful applications t0 the particular construction which, for tlief purpose of explanation, are made the subject of illustration.

lfi irre 1 is'a'top -planvievv of an insulator strucureembdying invention,

Qisa longitudinal' side view, partially i'nfelevat'idn 'and' partiallyy vin section, 'of the asignada/tain rig. 1

Figi' isa vie'vv', similar to the `top .portion of Fig.. 2, of a modified form of my invention, AFi'glr isaI'renlarg'edVdet-ail view, partially inf-elevation and partially.in section, vof a portinfiof the structure as shown in Figs. 2 mais, aid;

5 *and "are views,L similar 4to Fig. 3, -mediiied `forms of my invention. Figsl and 2, Athe structure comprises, in geieral, a substantially squir-y rel-cae structure includ-ing. oppositely spte "terrh'inal structures@ and 3 and a pludielectric tension rods 'or elements 4 connected therebetween..

fhe.terminal structure 2*, preferably constructed of metahis provided With a plurality'bf substantially truste-conical `openings- 6 sylvnmertieally arranged on a rcircle having' 2 its center On'the longitudinal central axis of the- A"structure, a socket terminal lportion 7; and

rzdielly dispesed reinforcing Webs prefer-l ably constituting-.integral parts ot the mem- -rlf e terminal s tr1 1cti irey 3- is constructed similarlyto the nier-uber 2 vvith the exception that a ball terminal member Y9 tis substituted socket for 'co-operation with-asimilar thereto.l Other terminal attaching meanssuch las ac lev-is and -a-n eye, may-be provided instead of the socket 7 and there e.

innumben'are preferably constructed of' porcelain of relatively. small diameter havingr truste-conical end piirtions- 1 1 disposed in the inventionn is concerned, are prefe'rably` exposed-and qol-istitute theonly .dielectric material o ergatingor connected between v the termina, str'ctnres, and each# 'element is preferablyfcenkstructed of only Tone homogeneous massfoi its material;

The ends r11-,las shown '4, are `,preferablyw f provided withv-egreovedyA may also be clamped,

vThe elements or rods' 4,here shown as eight# v more clearly serrated or roughened outer surfaces that may be constructed by glazing silica sand, porcelain particles or other ceramic aggregates of a granular nature thereto. Surfaces 12 on the member 2 in the opening 6 are alsopreferably roughened, as by attaching sand 4or` other particles thereto by'- means otvitreous enamel or other suitably hard or durable material.

The ends 11 andthesurfaces 12 are 'pro-Y vided Withlaye'rs 14 and15,-jrespectively,of asphaltum or other yieldable inatefrial"l and held together-by bodies 16 of cement, metal alloy or. other bonding material. The ends screW-threadedly mounted or otherwise secured in vrposition Withcushioningnieans similar to the layers' 14 and 1 5 disposed between theclamped sur-V faces, screw threads or other parte.

In the above described structure the send or porcelain-particles lare vpreferably large enough and the interstices therebetweenldeep enough to permit effective interlocking thereof with the bodies 16, lbetween-the members 2 and 4, against tension-forces, the layers 414 and 15 ci yielding material assuming none of the load-in shear. A yieldable pad or element 17 may be placed between-the head y of each element 4 and the bottom of its corresponding recess 2 to cushion rela-tive longitudinal expansion or? movement? of the adjacent vparts:

In the above described structure, since the elements 4 are oi' relatively I small' 'cross-sectional area,- dil'licul-ics ordinarily occur/ring during-the manufacture of 'relatively thick bodies are avoided andY thetotalI tensile strengthfof the structure is veryfmaterially increa'sedover asimilar-structure having a single element 4 of the same material and of the same tota-lf cross-sectional area.

VThe elements are preferably; arranged parallel to each other to subdivide the tension loadland to avoid lateralv component fracturing-Istiesses 'which tendto disrupt the relativelyhard material thereof." Further, since theyieldable 'films' 14 and-15 Aare disposed between e'ach end of each :element '4 and theftermin'al struc-tures .QV/andv, there are' provided four yielding elements or means inseries With leachy element 4 .between the-terminals y2 and 3.` YVThis construction compensates for miner 4'discrepaintiesint the lengths and shapesofthe rods l4 and tends:

to balance the subdivided tensiony loads rela;- openings AThe elements v4, elthoulgfh4l not so l restricted sof-far as the vbroadest aspect of my,

tivefte each1 'other vAsshovvn Fig-3, therodsfi, instead o" being. permanently ant'fhored in .A aunitaryY terminal, stifucture, are severallyv provided With-angindividual metalcapfor terminal element 1'9 in which they are similarly anchored orsecu-red.A 'The menleers 19 yare provided With'- f studs 20y for AAVattachment' to internally,` screw thre'adedbosses 21 constituting integrall parts of l-ancemrnen terminal structure .29 haw Y ing a clevis terminal portion 23 thereon. This construction permits easier replacement of the individual rods 4 in case of damage thereto.

As shown in Fig. 5, in place of the frustoconical ends 11 of the structure of Figs. 1 and 2, the elements 4 are provided with cylindrical ends 25 of substantially the same diameter as the body portions of the rods 1, are similarly provided with sanded or otherwise suitably roughened outer surfaces and are similarly secured to a common terminal structure i 27 having attaching means 28 thereon. This construction permits the composite dielectric portion of the insulator, consisting of all of the elements 4, to be of smaller lateral dimension or diameter.

An electrostatic stress distributing shield or element 30, shown in connection with Fig. 5, to widely distribute the electrostatic field and keep it away from the rods 4 in a manner heretofore suggested may be also, provided in the other forms of my invention.

In Fig. 6, the structure is similar to that shown in Fig. 5 with the exception that, instead of the common metal terminal member 27, a common refractory or ceramic terminal structure 32 similar thereto is provided for the rods 4 and a single metal cap terminal member 33 is secured in position over the element 32. In this structure, in addition to the yieldable films between the elements 4 and the cement bodies 16 and between the cement bodies 16 and the element 32, similar yielding bodies may be placed between the element 32 and a cement body 35 and between the cement body 35 and the terminal member 33 thereby providing additional means for compensating uneven load and expansion forces.

By my invention, an exceedingly simple and effective insulator is obtained that is free of the defects occurring in the production of the large masses of porcelain and other materials, that provides increased surface holding contact between the parts, that has better loading characteristics and is, in general, an improvement over insulators heretofore suggested that employ dielectric material under tension.

It is further to be understood that, where the term inorganic is used in the claims, it is intended to include all of those relatively hard, ceramic, permanently water-proof or similar materials as distinguished from wood, hard rubber, bakelite micarta and other materials of similarly readily recognizable qualities not effectively suited to the purposes of my invention.

It is also, contemplated that rods or elements of organic or non-refractory nature coated with inorganic or refractory materials may be employed within the purview of certain features of my invention, such as that wherein the lateral component stresses, which might disrupt such coatings, are kept out of the elements.

I claim as my invention:

1. A tension insulator comprising oppositely spaced terminal structures, a plurality of insulating elements connected therebetween to subdivide the tension load and yieldable means between the insulating material of each element and the next adjacent part of one of the terminal structures to balance the load divisions relative to each other.

2. A tension insulator comprising oppositely spaced terminals including registering socket portions, a plurality of elongated insulating elements connected between the terminals wit-h the opposite ends of each in registering sockets to subdivide the tension load and yieldable means between the insulating material of each element and the next adjacent part of one of its sockets to balance the load divisions relative to each other.

3. A tension insulator comprising oppositely-spaced terminals including registering lportions providing substantially frusto-conical sockets, a plurality of elongated insulating elements connected between the terminals to subdivide the tension load and having frusto-conical ends in said sockets and yieldable means between the insulating material of each element and the next adjacent part of one of its sockets to balance the load divisions relative to each other.

4. A tension insulator comprising oppositely-spaced terminals, a plurality of elongated insulating elements connected therebetween in the form of a substantially squirrelcage structure to subdivide the tension load and yieldable means between the insulating material of each element and the next adjacent part of one of the terminal structures to balance the load divisions relative to each other.

5. A tension insulator comprising oppositely-spaced terminals each including a disklike member including a central outer-side i HOBAR-T M. KRANER. 

